The present invention provides method and apparatus to continuously monitor the concentration of a component in the exhaust hydrocarbon a vapor recovery system. Monitoring is provided to prevent excess loss of, for example hydrocarbons into the atmosphere to both reduce product loss and to notify equipment operators of a potential system failure or system deterioration which could lead to operating difficulty, safety hazards and possible pollution control violation.
In accordance with the present invention the vent gas from the solvent recovery unit is continuously monitoring and analyzed by a nondispersive analyzer. The concentration of hydrocarbon in the exhaust gas is then converted to an electrical signal which provides input signals to a two level alarm device and to a recording and display device. The recording and display device is time actuated to periodically store the instantaneous concentration of the selected component at selected intervals and then display an average overall concentration for the selected period of time as a permanent record.
The two level alarm system is adapted to actuate the display device at a first selected concentration of the component in the vent gas to inform the operating personnel of possible system deterioration or system failure and further to provide a permanent record of the hydrocarbon concentration at the time. Additionally a second level alarm is provided when the concentration of the component in the vapor has recorded a second limit to shut down the vapor recovery equipment, for example in the event of a total failure of the system.
More particularly, the present invention provides a method and device for continuously analyzing, retaining and periodically displaying the concentration of a selected component in an emission gas from a vapor recovery unit. A timing device is provided to periodically display the average concentration of the component in the off gas and the concentration is continuously monitored and supplied to first and second level alarms to be actuated at selected concentrations of the component where when the concentration reaches the first level the concentration is displayed and where if the concentration reaches the second level the vapor recovery unit may be shut down.
While various arrangements within the scope of the present invention will occur to those skilled in the art upon reading the disclosure set forth hereinafter, one example in accordance with the present invention is illustrated in the accompanying figures where it will be understood the accompanying figures and the description are not by way of limitation.